The present invention pertains to epoxy novolac resins, their novolac resin precursors and a process for preparation of said novolac resins.
High functional (average functionality of about 5-8) epoxy novolac resins have high Tg values when cured with sulfanilimide. However, they are very difficult to prepare due to the high viscosity of the novolac resin precursors. The present invention provides a method for preparing epoxy novolac resins having high Tg values when cured with typical epoxy curing agents such as, for example, methylenedianiline, diaminodiphenylsulfone, sulfanilimide and the like while having a relatively low melt viscosity.